Compound and electronic device including same

ABSTRACT

A compound is disclosed. The compound has a formula of MA x L y , wherein:
         A is       

     
       
         
         
             
             
         
       
         
         
           
             L is one of 
           
         
       
    
     
       
         
         
             
             
         
       
         
         
           
             M is a metal having six valence electrons, x is an integer from 1-3, y is an integer from 0-2, x+y=3, any of R a -R b  and R 1 -R 3  is independently selected from a group consisting of hydrogen, deuterium, fluorine, chlorine, bromine, iodine, N(R 1 ) 2 , N(Ar 1 ) 2 , C(═O)Ar 2 , P(═O)Ar 3   2 , S(═O)Ar 4 , S(═O) 2 Ar 5 , CR 2 ═CR 3 Ar 6 , CN, NO 2 , Si(R 4 ) 3 , B(OR 5 ) 2 , OSO 2 R 6 , a linear alkyl having 1 to 40 carbon atoms, a C 1 -C 40  alkoxyl, a C 1 -C 40  alkylthiol, a C 3 -C 40  branched alkyl, a C 3 -C 40  cycloalkyl, a C 3 -C 40  branched alkoxyl, a C 3 -C 40  cyclic alkoxyl, a C 3 -C 40  branched alkylthiol and a C 3 -C 40  cyclic alkylthiol, any of R 1 -R 6  is one of a hydrogen and an alkyl, any of Ar 1 -Ar 6  is one of a hydrogen and an aryl, and any of R 4 ˜R 11  and R 13 ˜R 15  is independently selected from a group consisting of a hydrogen, a deuterium, a halogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted cycloalkyl and a substituted or unsubstituted aryl.

CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY

The application claims the benefit of the U.S. Provisional Patent Application No. 62/287,724, filed on Jan. 27, 2016, at the U.S. Intellectual Property Office, the disclosures of which are incorporated herein in their entirety by reference.

FIELD OF THE INVENTION

The present invention is related to an organic compound. In particular, the present invention is related to an organic compound for use in an electronic device.

BACKGROUND OF THE INVENTION

It is well known that the organic light emitting diode (OLED) was initially invented and proposed by the Eastman Kodak Company through a vacuum evaporation method. Tang and VanSlyke of the Kodak Company deposited an electron transport material such as tris(8-hydroxyquinolinato)aluminium (abbreviated as Alq3) on a transparent indium tin oxide (abbreviated as ITO) glass formed with an organic layer of aromatic diamine thereon, and subsequently completed the fabrication of an organic electroluminescent (EL) device after a metal electrode was vapor-deposited onto the Alq3 layer. The organic EL device has become a new generation lighting device or display because of high brightness, fast response speed, light weight, compactness, true color, no difference in viewing angles, the lack of any LCD backlight plates, and low power consumption.

Recently, some interlayers such as an electron transport layer and a hole transport layer have been added between the cathode and the anode to increase the current efficiency and power efficiency of the OLEDs. For example, an OLED 100 shown as FIG. 1 is designed to be formed with a cathode 11, an electron injection layer 12, an electron transport layer 13, a light emitting layer 15, a hole transport layer 17, a hole injection layer 18, an anode 19 and the a substrate 20.

In the device function concept, the light emitted by the OLED 100 results from excitons produced by the recombination of electrons and holes in the light emitting layer 15, wherein the formed excitons have configurations with two contrary spin directions, which include a singlet excited state and a triplet excited state. Thus, when the two electrons having two contrary spin directions in each of the electron pairs in the basic state are excited, about 25% of the excitons transition to the singlet excited state to form the singlet excitons, and 75% of the excitons transition to the triplet excited state to form the triplet excitons. The light generated from the singlet excitons is called fluorescent light while the light generated from the triplet excitons is called phosphorescent light.

So, when a fluorescent material is used as the light-emitting layer 15 of the OLED 100, about 25% of the excitons are used to emit light, and the other 75% of the excitons in the triplet excited state are lost through a non-luminescence mechanism. For this reason, the general fluorescent material performs at a maximum quantum yield of 25%, a limit which amounts to an external quantum efficiency of 5% in the device. If a phosphorescent material is used as the light-emitting layer 15 of the OELD 100, the material will be advantageous to perform at a quantum yield of 75% resulting from the triplet excitons. The singlet excitons can become triplet excitons through an intersystem crossing, and accordingly the internal quantum efficiency of the phosphorescent material will reach 100%. However, when the above-mentioned two materials are used with the OLED devices, there will be individual advantages and shortcomings. When a fluorescent material is used as a material in the OLED devices, the device lifetime will be long but the light emitting efficiency is low, and when a phosphorescent material is used, the light emitting efficiency is high but the device lifetime is short.

Therefore, to enhance the OLED devices having the advantages of both good light efficiency and long lifetime, research has been conducted to introduce heavy atoms such as the transition metals, e.g. Ir, Pt, Os, Ru, Eu, Re, etc., into the fluorescent materials in the light emitting layer. Using the heavy atom effect to generate the spin-orbital coupling, the probability of transitioning the excitons from the basic state to the triplet state in the system is improved. Accordingly, the internal quantum efficiency in the OLED devices can reach 100%.

In addition, in subsequent studies, it was found that, by doping impurities in different concentrations in the light emitting layer in the OLED devices, the transition of the energy of the light emitting host materials to the dopants to change the colors of the light emitting materials and the light emitting efficiency are achieved, so that OLED devices emitting the three colors of red, green and blue light are obtained. These studies simultaneously pointed out the importance of the selection of the materials used in various layers in the OLED devices, where the materials include hole transport materials, electron transport materials, host light emitting materials and dopants for different colors of the light. In addition, it will not be possible to meet the requirements unless continuous research and improvements to the physical properties of the materials themselves such as the energy gap, thermal properties, and morphology are accomplished.

Although there are a lot of dopant materials related to emitting the three primary colors red, green and blue, no suitable solution has been reached. Therefore, the inventors of the present invention undertook their best efforts to perform the inventive research and disclosed herein a series of dibenzoxepin pyridine complexes of metal having six covalent electrons and being the central atom, as green light emitting dopant materials used for a light emitting layer in OLED devices.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a compound is disclosed. The compound has a formula of MA_(x)L_(y), wherein:

A is

L is one of

M is a metal having six valence electrons, x is an integer from 1-3, y is an integer from 0-2, x+y=3, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of hydrogen, deuterium, fluorine, chlorine, bromine, iodine, N(R¹)₂, N(Ar¹)₂, C(═O)Ar², P(═O)Ar³ ₂, S(═O)Ar⁴, S(═O)₂Ar⁵, CR²═CR³Ar⁶, CN, NO₂, Si(R⁴)₃, B(OR⁵)₂, OSO₂R⁶, a linear alkyl having 1 to 40 carbon atoms, a C₁-C₄₀ alkoxyl, a C₁-C₄₀ alkylthiol, a C₃-C₄₀ branched alkyl, a C₃-C₄₀ cycloalkyl, a C₃-C₄₀ branched alkoxyl, a C₃-C₄₀ cyclic alkoxyl, a C₃-C₄₀ branched alkylthiol and a C₃-C₄₀ cyclic alkylthiol, any of R¹-R⁶ is one of a hydrogen and an alkyl, any of Ar¹-Ar⁶ is one of a hydrogen and an aryl, and any of R₄˜R₁₁ and R₁₃˜R₁₅ is independently selected from a group consisting of a hydrogen, a deuterium, a halogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted cycloalkyl and a substituted or unsubstituted aryl.

In accordance with another aspect of the present invention, an electronic device made using a compound is disclosed. The electronic device includes a compound having a formula of MA_(x)L_(y), wherein:

A is

L is one of

M is a metal having six valence electrons, x is an integer from 1-3, y is an integer from 0-2, x+y=3, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of hydrogen, deuterium, fluorine, chlorine, bromine, iodine, N(R¹)₂, N(Ar¹)₂, P(═O)Ar³ ₂, S(═O)Ar⁴, S(═O)₂Ar⁵, CR²═CR³Ar⁶, CN, NO₂, Si(R⁴)₃, B(OR⁵)₂, OSO₂R⁶, a linear alkyl having 1 to 40 carbon atoms, a C₁-C₄₀ alkoxyl, a C₁-C₄₀ alkylthiol, a C₃-C₄₀ branched alkyl, a C₃-C₄₀ cycloalkyl, a C₃-C₄₀ branched alkoxyl, a C₃-C₄₀ cyclic alkoxyl, a C₃-C₄₀ branched alkylthiol and a C₃-C₄₀ cyclic alkylthiol, any of R¹-R⁶ is one of hydrogen and an alkyl, any of Ar¹-Ar⁶ is one of a hydrogen and an aryl, and any of R₄˜R₁₁ and R₁₃˜R₁₅ is independently selected from a group consisting of a hydrogen, a deuterium, a halogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted cycloalkyl and a substituted or unsubstituted aryl.

When the compounds disclosed in the present invention are used as the materials in the electronic device, it is possible to operate the electronic device at a low operation voltage, so that the electronic device has an increased lifetime and has an excellent light emitting efficiency.

The above objectives and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an OLED structure according to prior art;

FIGS. 2 and 3 are NMR spectrums of compounds of the nitrogen-substituted dibenzoxepinpyridine according to the present invention;

FIGS. 4-7 are NMR spectrums of compounds of the dibenzoxepin pyridine complexes of metal having six covalent electrons and being the central atom according to the present invention; and

FIG. 8 is an OLED structure according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for the purposes of illustration and description only; they are not intended to be exhaustive or to be limited to the precise form disclosed.

The present invention discloses a compound being a metal complex with at least one dibenzoxepin pyridine ligand or its derivatives, wherein the compound has a formula of MA_(x)L_(y), wherein:

A is

L is one of

M is a metal having six valence electrons, x is an integer from 1-3, y is an integer from 0-2, x+y=3, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of hydrogen, deuterium, fluorine, chlorine, bromine, iodine, N(R¹)₂, N(Ar¹)₂, C(═O)Ar², P(═O)Ar³ ₂, S(═O)Ar⁴, S(═O)₂Ar⁵, CR²═CR³Ar⁶, CN, NO₂, Si(R⁴)₃, B(OR⁵)₂, OSO₂R⁶, a linear alkyl having 1 to 40 carbon atoms, a C₁-C₄₀ alkoxyl, a C₁-C₄₀ alkylthiol, a C₃-C₄₀ branched alkyl, a C₃-C₄₀ cycloalkyl, a C₃-C₄₀ branched alkoxyl, a C₃-C₄₀ cyclic alkoxyl, a C₃-C₄₀ branched alkylthiol and a C₃-C₄₀ cyclic alkylthiol, any of R¹-R⁶ is one of a hydrogen and an alkyl, any of Ar¹-Ar⁶ is one of a hydrogen and an aryl, and any of R₄˜R₁₁ and R₁₃˜R₁₅ is independently selected from a group consisting of a hydrogen, a deuterium, a halogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted cycloalkyl and a substituted or unsubstituted aryl.

Preferably, M is one of iridium and platinum, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of a hydrogen, an alkyl having 1 to 4 carbon atoms and an aryl having 1 to 6 carbon atoms, and any of R¹-R⁶ is one of a hydrogen and an C1-C6 alkyl, any of R₄˜R₁₁ and R₁₃˜R₁₅ is one selected from a group consisting of a hydrogen, a deuterium, a fluorine, a chlorine, a bromine, an alkyl having 1 to 4 carbon atoms and an aryl having 1 to 6 carbon atoms, two adjacent groups of R₄˜R₇ are optionally jointed to form a fused ring, and the fused ring is a phenyl ring.

More preferably, any of R_(a)-R_(b), R₁-R₁₁ and R₁₃˜R₁₅ is one selected from a group consisting of a hydrogen, a methyl, an isobutyl and a phenyl, and any of Ar¹-Ar⁶ is one of a hydrogen and an phenyl.

The compound of a metal complex with at least one dibenzoxepin pyridine ligand or its derivatives possess a light emitting property, and has a property to transition the excitons from the singlet excited state into the triplet excited state. Thus, when the compound or its derivatives are used for a phosphorescent OLED device, the compound is used as a material of a light emitting layer.

The compound of a metal complex with at least one dibenzoxepin pyridine ligand or its derivatives is represented by the following Formula 1-0 and Formula 2-0:

wherein M is iridium or platinum, x is an integer from 1-3, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of hydrogen, deuterium, fluorine, chlorine, bromine, iodine, N(R¹)₂, N(Ar¹)₂, C(═O)Ar², P(═O)Ar³ ₂, S(═O)Ar⁴, S(═O)₂Ar⁵, CR²═CR³Ar⁶, CN, NO₂, Si(R⁴)₃, B(OR⁵)₂, OSO₂R⁶, a linear alkyl having 1 to 40 carbon atoms, a C₁-C₄₀ alkoxyl, a C₁-C₄₀ alkylthiol, a C₃-C₄₀ branched alkyl, a C₃-C₄₀ cycloalkyl, a C₃-C₄₀ branched alkoxyl, a C₃-C₄₀ cyclic alkoxyl, a C₃-C₄₀ branched alkylthiol and a C₃-C₄₀ cyclic alkylthiol, any of R¹-R⁶ is one of a hydrogen and an alkyl, any of Ar¹-Ar⁶ is one of a hydrogen and an aryl, and any of R₄˜R₁₁ and R₁₃˜R₁₅ is independently selected from a group consisting of a hydrogen, a halogen, a deuterium, a substituted or unsubstituted alky, a substituted or unsubstituted cycloalkyl 1 and a substituted or unsubstituted aryl.

Preferably, A is the compound of the dibenzoxepinpyridine and the derivatives thereof and can be one selected from the group consisting of the following.

Preferably, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of a hydrogen, an alkyl having 1 to 4 carbon atoms and an aryl having 1 to 6 carbon atoms, and any of R¹-R⁶ is one of a hydrogen and an C1-C6 alkyl, any of R₄˜R₁₁ and R₁₃˜R₁₅ is one selected from a group consisting of a hydrogen, a deuterium, a fluorine, a chlorine, a bromine, an alkyl having 1 to 4 carbon atoms and an aryl having 1 to 6 carbon atoms, two adjacent groups of R₄˜R₇ are optionally jointed to form a fused ring, and the fused ring is a phenyl ring.

More preferably, any of R_(a)-R_(b), R₁-R₁₁ and R₁₃˜R₁₅ is one selected from a group consisting of a hydrogen, a methyl, an isobutyl and a phenyl, and any of Ar¹-Ar⁶ is one of a hydrogen and an phenyl.

More preferably, when L is represented by the following formula,

L can be one selected from a group consisting of the following ligands.

And when L is represented by the following formula,

L can be one selected from a group consisting of the following ligands.

Take the compound represented by Formula 1-0 as an example, the compound includes the combinations of the following A and L selected from the followings.

According to a first embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-1.

According to a second embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-2.

According to a third embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-3.

According to a fourth embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-4.

According to a fifth embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-5.

According to a sixth embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-6.

According to a seventh embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-7.

According to a eighth embodiment of the present invention, the compound of a metal complex with one dibenzoxepin pyridine ligand is represented by Formula 1-8.

According to a ninth embodiment of the present invention, the compound of a metal complex with one dibenzoxepin pyridine ligand is represented by Formula 1-9.

According to a tenth embodiment of the present invention, the compound of a metal complex with three dibenzoxepin pyridine ligands is represented by Formula 1-10.

According to an eleventh embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-11.

According to a twelfth embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-12.

According to a thirteenth embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-13.

According to a fourteenth embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-14.

According to a fifteenth embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-15.

According to a sixteenth embodiment of the present invention, the compound of a metal complex with two a dibenzoxepin pyridine ligands is represented by Formula 1-16.

According to a seventeenth embodiment of the present invention, the compound of a metal complex with two dibenzoxepin pyridine ligands is represented by Formula 1-17.

The iridium in each of the above Formulae can be replaced with platinum. A variety of substituted or unsubstituted compounds of a metal complex with a dibenzoxepinpyridine belong to the scope covered by the present invention, and can be synthesized using the following steps.

Synthesis Method of the First to the Seventeenth Embodiments

The synthesis method of the compound of an iridium complex with a dibenzoxepinpyridine includes the following steps.

1. Preparation of a Nitrogen (N)-Substituted Tribenzoxepin (TBO) Ligand

1.1 The synthesis method of the N-substituted TBO ligand includes the following steps.

100 g (1 eq) of diphenyl ether (represented by Formula a) and n-butyl lithium (n-BuLi) anhydrous tetrahydrofuran (THF) are put in a 2 L reacting flask, and 587 mL of 2.5M N-butyl lithium is added to the reacting flask at a temperature of −78° C. to form a first solution, and then the temperature of the first solutions is raised to 25° C. and the first solutions reacts for 24 hours to obtain a semi-product. After the semi-product is cooled to a temperature of −40° C., trimethyl borate (B(OMe)₃) is added to form a second solution. After its temperature is raised to 25° C., 3N hydrochloric acid is added to the second solution until the solution becomes acidic, to produce 60 g of the compound represented by Formula b. Yield is 52%. The chemical reaction is as follows.

50 g (1 eq) of the compound represented by Formula b and 60.4 g (1 eq) of 2,3-dibromopyridine are put in a 1000 mL reacting flask, and then 500 mL of isobutanol, 274 g of Cs₂O₃ and 50 mL of water are added. After removing the air from the reaction flask by vacuum, 3.5 g of tris(dibenzylideneacetone)dipalladium (Pd₂(dba)₃) and 2.22 g of tri-tert-butylphosphonium tetrafluoroborate (P(t-Bu)₃HBF₄) are added and react at a temperature of 100° C. for 4 hours After being cooled, 200 mL of water is added to terminate the reaction. 600 mL of ethyl acetate are used to extract the semi-product. After the organic solvent layer is dried by vacuum, the semi-product is chromatographed through the silica gel column, and is eluted by solvent including N-butane and ethyl acetate in a ratio of 3:1. After the solvents are dried by vacuum, the solvent including N-butane and ethyl acetate is used to crystallize the product to obtain 45 g of a yellowish solid, which is the compound represented by Formula c. Yield is 72% The chemical reaction is as follows.

1.2 Using the same synthesis method and replacing 60.4 g of 2,3-dibromopyridine with 64 g of 2,3-dibromo-4-methyl pyridine or 64 g of 2,3-dibromo-5-methyl pyridine, the compound represented by Formula d-1 or d-2 is obtained. The chemical reaction is as follows.

1.3 Using the same synthesis method and replacing 60.4 g of 2,3-dibromopyridine with 69.2 g of 2,3-dibromo-5-chloropyridine, the compound represented by Formula e is obtained. The chemical reaction is as follows.

1.4 Instead, 30 g (1 eq) of the compound represented by Formula e and 13.1 g (1 eq) of phenylboric acid are added to a 1 L reaction flask, 200 mL of toluene and 20 mL of ethanol are added, and then 3 eq. of K₂CO₃ aqueous solution (which is 44.5 g of K₂CO₃ dissolved in 120 mL of water) are added. After removing the air from the reaction flask by vacuum, 0.602 g of Pd(OAc)₂ and 3.76 g of dicyclohexylphosphino)biphenyl (P(Cy)₂(2-biphenyl)) are added under a nitrogen atmosphere, the solution is heated and refluxed t at a temperature of 100° C. for 12 hours. It is cooled after the reaction is terminated. After the organic solvent layer is dried by vacuum, the semi-product is eluted by solvent including N-butane and ethyl acetate in a ratio of 3:1, and is chromatographed and purified through the silica gel column. The compound represented by Formula f is obtained. The chemical reaction is as follows.

The compounds represented by Formula c, Formula d-1, Formula d-2, Formula e and Formula f are all N-substituted TBO ligands. In addition, bromine in the reactant 2,3-dibromopyridine can be replaced by the other halogen elements, so that 2,3-diiodopyridine can also be a candidate as a reactant. Moreover, it can be seen from the above chemical reactions that, if an iridium complex with at least one dibenzoxepin pyridine ligand having a substituted group on the pyridinyl group contained in the dibenzoxepin pyridine ligand, then the 4th, 5th, or 6th position on the reactant 2,3-dibromopyridine (or 2,3-diiodopyridine instead) should be substituted by a prior substitution reaction.

2. Preparation of an Iridium Dimer 2.1 Preparation of N-Substituted TBO Iridium Dimer

Taking the compound of the N-substituted TBO ligand (N-TBO) represented by Formula c as an example, the synthesis method of the N-substituted TBO iridium dimer includes the following steps.

10 g (1 eq) of iridium (III) chloride and 16.7 g (2.2 eq) of N-TBO ligand are added in a 250 mL round bottomed flask. 120 mL of 2-ethoxyethanol and 40 mL water are then added. The mixture is refluxed for 24 hrs at a temperature of 120° C. under a nitrogen atmosphere to form the product. After cooling to room temperature, the product is washed using methanol and is filtered to obtain the precipitate. The precipitate is dried in vacuum, and 17 g of the N-substituted iridium dimer represented by Formula g is obtained. Yield is 83.7%. The chemical reaction is as follows.

2.2 Preparation of Ir(2-phenylpyridine)₂ dimer (Ir(ppy)₂Cl dimer)

50 g (1 eq) of iridium (III) chloride and 52.8 g (2.4 eq) of 2-phenylpyridine are added in a 1000 mL round bottomed flask. 300 mL of 2-ethoxyethanol and 100 mL water are then added. The mixture is refluxed for 24 hrs at a temperature of 120° C. under a nitrogen atmosphere to form the product. After cooling to room temperature, the product is washed using methanol and is filtered to obtain the precipitate. The precipitate is dried in vacuum, and 68 g of the Ir(ppy)₂Cl dimer represented by Formula h is obtained. Yield is 89%. The chemical reaction is as follows.

3. Preparation of an Iridium Trifluoromethanesulfonate (Iridium Triflate)

3.1 Dissolve 5.0 g of the compound represented by Formula g in 100 mL of dichloromethane (CH₂Cl₂) to form a first solution. Dissolve 1.97 g of silver triflate (AgOTf) in 20 mL of methanol to form a second solution. Add the second solution to the first solution at a temperature of 0° C. to form a mixture. The mixture is stirred at room temperature for 6 hours. The mixture is then poured through a celite plug to remove silver chloride (AgCl) to form a third solution. The solvent contained in the third solution is evaporated by vacuum, and 5.2 g of the iridium triflate compound represented by Formula i is obtained. The chemical reaction is as follows.

3.2 Dissolve 5.0 g of the compound represented by Formula h in 100 mL of dichloromethane (CH₂Cl₂) to form a first solution. Dissolve 2.63 g of silver triflate (AgOTf) in 20 mL of methanol to form a second solution. Add the second solution to the first solution at a temperature of 0° C. to form a mixture. The mixture is stirred at room temperature for 6 hours. The mixture is then poured through a celite plug to remove silver chloride (AgCl) to form a third solution. The solvent contained in the third solution is evaporated by vacuum, and 5.9 g of the iridium triflate compound represented by Formula j is obtained. The chemical reaction is as follows.

4. Preparation of the Iridium Complex with at Least One Dibenzoxepin Pyridium Ligand

4.1 Dissolve 5 g (1 eq) of the compound represented by Formula g, 3.5 g (10 eq) of acetyl acetate (acac) and 9.6 g (20 eq) of potassium carbonate (K₂CO₃) in 100 mL of 2-ethoxyethanol and react for at a temperature of 80° C. for 24 hours. After being cooled and filtered by a vacuum filter, the product is eluted with water and methanol, and is dried by vacuum, to obtain a yellowish solid. The yellowish solid is dissolved and poured through a celite filter and is washed with CH₂Cl₂ to obtain a semi-product. CH₂Cl₂ is removed from the semi-product by vacuum, to obtain the iridium complex with two dibenzoxepin pyridine ligands represented by Formula 1-12. The chemical reaction is as follows.

In a 250 mL round bottomed flask, dissolve 5 g of the compound represented by Formula g and 1.3 g (2.4 eq) of 2-phenylpyridine in 100 mL of 2-ethoxy ethanol to form a solution. React the solution at a temperature of 80° C. for 24 hours to form a mixture. The mixture is then poured onto a celite bed and the product is eluted using CH₂Cl₂. The CH₂Cl₂ contained in the product is evaporated by vacuum, and 3.2 g of the compound represented by Formula 1-1 is obtained. The yield is 55%. The chemical reaction is as follows.

4.3 Alternatively, add and dissolve 5 g (1 eq) of the compound represented by Formula g and 1.3 g (1.2 eq) of 2-phenylpyridine in 100 mL 2-ethoxyethanol in a 250 mL round bottomed flask to react at a temperature of 80° C. for 24 hours to obtain the product. Use vacuum distillation to remove the 2-ethoxyethanol solvent, and add methanol to obtain a solid mixture. The solid mixture is dissolved in dichloroethane (CH₂Cl₂) and the solution is poured through a celite filter and is eluted with CH₂Cl₂ to obtain a semi-product. CH₂Cl₂ is removed from the semi-product by vacuum, and 100 mL of N-hexane is added to elute all solid composition. The solid composition is dried by vacuum, and is dissolved in CH₂Cl₂ and elute the product by CH₂Cl₂ solvent by a silica column. After removing the solvent, 3.2 g of the yellowish-orange solid, which is the compound represented by Formula 1-1, are obtained. Yield is 55%. The chemical reaction is as follows.

4.4 If the reactant 2-phenylpyridine is replaced by the compound represented in the following reaction, using similar reaction steps, the compound represented by Formula 1-10, Formula 1-2, Formula 1-3 or Formula 1-4 will be respectively obtained. The chemical reactions are as follows.

4.5 Alternatively, in a 250 mL round bottomed flask, dissolve 5 g (1 eq) of the compound represented by Formula j and 2.9 g (1.2 eq) of the compound represented by Formula c in 100 mL of 2-ethoxy ethanol to form a solution. React the solution at a temperature of 80° C. for 24 hours to form a mixture. The mixture is then poured onto a celite bed and the product is eluted using CH₂Cl₂. The CH₂Cl₂ contained in the product is evaporated by vacuum, and the compound represented by Formula 1-8 is obtained. The chemical reaction is as follows.

Table 3 shows several compounds as examples of the iridium complexes with at least one dibenzoxepinpyridine having combinations of different ligands A and L, but it is not limited to the examples in Table 3. These compounds can also be synthesized using the above steps.

TABLE 3

General Purification Method

The iridium complexes with at least one dibenzoxepin pyridine ligand are purified by heating with zone refine sublimation in a vacuum environment of 10⁻⁶ torr.

It can be seen from the above descriptions that all the N-substituted dibenzoxepinpyridine compounds and the iridium complexes with at least one dibenzoxepinpyridine are within the scope of the present invention. In addition, several N-substituted dibenzoxepinpyridine compounds and iridium complexes with at least one dibenzoxepinpyridine synthesized in the present invention were analyzed by a nuclear magnetic resonance (NMR) spectrometer to identify their structures. The spectrum diagrams of the compounds represented by Formulae c, d-1, 1-8, 1-1 and 1-12 synthesized in the present invention are sequentially shown in FIGS. 2-7. Accordingly, the obtained compounds are confirmed as the N-substituted dibenzoxepinpyridine compounds or the iridium complexes with at least one dibenzoxepinpyridine.

OLED Device

The steps to manufacture an OLED device using the iridium complexes with at least one dibenzoxepinpyridine of the present invention are as follows.

Pretreatment to the Substrate

First, dipping an ITO glass substrate having a thickness of 1500 Å of the ITO layer in distilled water containing a detergent (supplied by Fischer Co.). The ITO glass substrate is washed using ultrasonic for 30 minutes, washed twice by distilled water using ultrasonic for 10 minutes each time, washed with isopropanol, acetone, and methanol solvents using ultrasonic, and dried with nitrogen gas. The dried ITO glass substrate is then put in an oxygen plasma cleaner to treat the surface of the ITO glass substrate using oxygen plasma for 5 minutes to clean the surface, so as to increase the work function of the ITO glass surface.

Coating of the Organic Layer

The treated ITO glass substrate is placed in a vacuum evaporation machine and a variety of organic materials are sequentially deposited on the ITO glass substrate, to manufacture the OLED device.

It is possible to use an ink jet printing method to replace the evaporation method. The variety of organic materials are coated on the ITO glass substrate using an ink-jet printer, and then are hardened using a baking process to manufacture the OLED device. If the ink-jet printing method is used, the consumption of the organic materials will be much less than when using the evaporation method. Thus the material cost to manufacture the OLED electronic device is dramatically reduced.

Alternatively, it is possible to use an aluminum coated glass as a substrate to manufacture the OLED device. After cleaning the substrate, an evaporation or ink jet printing method is used to coat a variety of the organic materials in a coating sequence that is reverse of the order mentioned above to manufacture the OLED device.

Evaluation to the OLED Device

FIG. 8 is a structure of an OLED device 200 manufactured according to the disclosures in the present invention. As shown in FIG. 8, it includes, from bottom to top, an ITO (as an anode) layer 29 coated on a glass substrate 30, a hole injection layer 28, which includes a first hole injection (HI-1) layer 28-1 and a second hole injection (HI-2) layer 28-2 containing a hole injection dopant (HID) material therein, a hole transport layer 27, which including a first hole transport (HT-1) layer 27-1 and a second hole transport (HT-2) layer 27-2, a light emitting layer 25, which contains a green light emitting host (GH1) material and a green light emitting dopant (GD) material, an electron transport (ETL) layer 23 containing an electron transport dopant (ETD) material, an electron injection (EI) layer 22, and a cathode 21. If necessary, a hole block layer (not shown) can be disposed between the light emitting layer 25 and the electron transport layer 23, or an electron block layer (not shown) can be disposed between the light emitting layer 25 and the hole transport layer 27. The material and thickness of each layer used in the OLED devices for the evaluation are shown in Table 4. Table 5 further shows the formulae of the materials.

TABLE 4 layer dopant green host green dopant dopant hole hole in hole hole hole in light in light electron in hole Hole transport injection injection transport transport emitting emitting transport transport injection anode layer 1 layer 2 layer 2 layer 1 layer 2 layer layer layer layer layer cathode material ITO HAT HI-2 HAT HT-1 HT-2 GH Formula ETL Liq Liq Al 1-1, 1-8, 1-12, 1-13 or 1-15 thickness 1500 100 1235 65 100 100 360 40 227.5 122.5 15 1500 (Å) coating — 1 2 2 3 4 5 5 6 6 7 8 sequence

TABLE 5

  (HAT) HI-1

HI-2

HT-1

HT-2

GH Compound represented GD by Formula 1-1, 1-8, 1-12, 1-13 or 1-15

ETL

  (Liq) ETD

Table 6 shows the evaluation results of the OLED devices, which include Examples 1-8 using the compounds represented by Formula 1-1, 1-8, 1-12, 1-13 and 1-15, and the Comparative Examples 1-2 using the previous compounds. It can be seen from Table 6 that for the OLED devices using the compounds represented by Formula 1-1, 1-8, 1-12, 1-13 and 1-15 of the present invention, the current efficiency reaches up to the range of 65.2-78.7 cd/A, and the operation voltage is only in the 2.87-3.21 V range. In comparison, the OLED devices using the prior materials in Comparative Examples 1-2, the current efficiency can only reach the range of 63.6-66.2 cd/A, and the operation voltage is in the range of 2.95-3.0V. It can be seen that the OLED device using the metal complex with at least one dibenzoxepinpyridine ligand, in which the metal is a central atom having six covalent electrons as a dopant for the green light emitting layer, has a higher current efficiency and a low operation voltage and comparable chroma values for the green color. Moreover, due to the low operation voltage, it is assured that the light emitting material has a longer life time and the OLED device use substantially less power.

TABLE 6 at 1000 nits Compound, chroma, CIE Operation current represented system voltage efficiency Example by color ( x, y ) (V) (cd/A) 1 Formula green ( 0.356, 0.609) 3.01 78.7 1-1 2 Formula green (0.350, 0.611) 2.91 75.5 1-8 3 Formula green ( 0.361, 0.615) 2.87 70.8 1-12 4 Formula green (0.345, 0.617) 3.06 68.5 1-13 5 Formula green (0.348, 0.620) 3.21 65.2 1-15 Comparative Formula green (0.308, 0.629) 3.0  63.6 Example 1 A-1 Comparative Formula green (0.314, 0.630) 2.95 66.2 Example 2 A-2

Each of the electronic devices mentioned above can be applied to any device or apparatus having a display, such as one selected from a group consisting of an organic light emitting apparatus, a solar cell apparatus, an organic transistor, a detection apparatus, a computer monitor, a TV, a billboard, a light for interior or exterior illumination, a signaling light for interior or exterior illumination, a flexible display, a laser printer, a telephone, a cell phone, a remote control apparatus, a pad computer, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display, a vehicle electronic apparatus, a large area wall display, a theater screen, a stadium screen, a signaling apparatus, a personal digital assistant (PDA), a laptop computer, an industrial computer, a point of sales (POS), a heads-up display, a fully transparent display, and a touch display.

While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. 

What is claimed is:
 1. A compound having a formula of MA_(x)L_(y), wherein: A is

L is one of

M is a metal having six valence electrons, x is an integer from 1-3, y is an integer from 0-2, x+y=3, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of hydrogen, deuterium, fluorine, chlorine, bromine, iodine, N(R¹)₂, N(Ar¹)₂, C(═O)Ar², P(═O)Ar³ ₂, S(═O)Ar⁴, S(═O)₂Ar⁵, CR²═CR³Ar⁶, CN, NO₂, Si(R⁴)₃, B(OR⁵)₂, OSO₂R⁶, a linear alkyl having 1 to 40 carbon atoms, a C₁-C₄₀ alkoxyl, a C₁-C₄₀ alkylthiol, a C₃-C₄₀ branched alkyl, a C₃-C₄₀ cycloalkyl, a C₃-C₄₀ branched alkoxyl, a C₃-C₄₀ cyclic alkoxyl, a C₃-C₄₀ branched alkylthiol and a C₃-C₄₀ cyclic alkylthiol, any of R¹-R⁶ is one of a hydrogen and an alkyl, any of Ar¹-Ar⁶ is one of a hydrogen and an aryl, and any of R₄˜R₁₁ and R₁₃˜R₁₅ is independently selected from a group consisting of a hydrogen, a deuterium, a halogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted cycloalkyl and a substituted or unsubstituted aryl.
 2. A compound according to claim 1, wherein M is one of platinum and iridium.
 3. A compound according to claim 1, wherein any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of a hydrogen, an alkyl having 1 to 4 carbon atoms and an aryl having 1 to 6 carbon atoms.
 4. A compound according to claim 1, wherein any of R₄˜R₁₁ and R₁₃˜R₁₅ is one selected from a group consisting of a hydrogen, a fluorine, a chlorine, a bromine, an alkyl having 1 to 4 carbon atoms and an aryl having 1 to 6 carbon atoms, and any of R¹-R⁶ is one of a hydrogen and an C1-C6 alkyl.
 5. A compound according to claim 4, wherein two adjacent groups of R₄˜R₇ are optionally jointed to form a fused ring.
 6. A compound according to claim 5, wherein the fused ring is a phenyl ring.
 7. A compound according to claim 1, wherein any of R_(a)-R_(b), R₁-R₁₁ and R₁₃˜R₁₅ is one selected from a group consisting of a hydrogen, a methyl, an isobutyl, and a phenyl.
 8. A compound according to claim 1, wherein the formula of MA_(x)L_(y) is one selected from a group consisting of the following formulae 1-1 to 1-17:


9. A compound according to claim 1, wherein the compound is used as a material in a light-emitting layer of an organic light emitting diode (OLED).
 10. An electronic device comprising a compound having a formula of MA_(x)L_(y), wherein: A is

L is one of

M is a metal having six valence electrons, x is an integer from 1-3, y is an integer from 0-2, x+y=3, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of hydrogen, deuterium, fluorine, chlorine, bromine, iodine, N(R¹)₂, N(Ar¹)₂, C(═O)Ar², P(═O)Ar³ ₂, S(═O)Ar⁴, S(═O)₂Ar⁵, CR²═CR³Ar⁶, CN, NO₂, Si(R⁴)₃, B(OR⁵)₂, OSO₂R⁶, a linear alkyl having 1 to 40 carbon atoms, a C₁-C₄₀ alkoxyl, a C₁-C₄₀ alkylthiol, a C₃-C₄₀ branched alkyl, a C₃-C₄₀ cycloalkyl, a C₃-C₄₀ branched alkoxyl, a C₃-C₄₀ cyclic alkoxyl, a C₃-C₄₀ branched alkylthiol and a C₃-C₄₀ cyclic alkylthiol, any of R¹-R⁶ is one of hydrogen and an alkyl, any of Ar¹-Ar⁶ is one of a hydrogen and an aryl, and any of R₄˜R₁₁ and R₁₃˜R₁₅ is independently selected from a group consisting of a hydrogen, a halogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted cycloalkyl and a substituted or unsubstituted aryl.
 11. An electronic device according to claim 10, wherein M is one of platinum and iridium.
 12. An electronic device according to claim 10, wherein, any of R_(a)-R_(b) and R₁-R₃ is independently selected from a group consisting of a hydrogen, an alkyl having 1 to 4 carbon atoms and an aryl having 1 to 6 carbon atoms.
 13. An electronic device according to claim 10, wherein any of R₄˜R₁ and R₁₃˜R₁₅ is one selected from a group consisting of a hydrogen, a fluorine, a chlorine, a bromine, an alkyl having 1 to 4 carbon atoms and an aryl having 1 to 6 carbon atoms.
 14. An electronic device according to claim 13, wherein two adjacent groups of R₄˜R₈ are optionally jointed to form a fused ring, and the fused ring is a phenyl ring.
 15. An electronic device according to claim 10, wherein any of R_(a)-R_(b), R₁-R₁₁ and R₁₃˜R₁₅ is one selected from a group consisting of a hydrogen, a methyl, an isobutyl and a phenyl.
 16. An electronic device according to claim 10, wherein the formula of MA_(x)L_(y) is one selected from a group consisting of the following formulae 1-1 to 1-17.


17. An electronic device according to claim 10, wherein the electronic device is an OLED, and the OLED comprises: a first electrode; a second electrode; and a light emitting layer disposed between the first electrode and the second electrode, wherein the light emitting layer is made of the compound.
 18. An electronic device according to claim 17, wherein the electronic device further comprises an electron transport layer disposed between the light emitting layer and the first electrode, an electron injection layer disposed between the electron transport layer and the first electrode, a hole transport layer disposed between the light emitting layer and the second electrode, and a hole injection layer disposed between the hole transport layer and the second electrode, wherein the first electrode is a cathode and the second electrode is an anode.
 19. An electronic device according to claim 18, wherein any one of the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, the electron injection layer and the combination thereof is formed by one of an evaporation and an ink jet printing method.
 20. An electronic device according to claim 10, wherein the electronic device is used as one selected from a group consisting of an organic light emitting apparatus, a solar cell apparatus, an organic transistor, a detection apparatus, a flat panel display, a computer monitor, a TV, a billboard, a light for interior or exterior illumination, a signal light for interior or exterior illumination, a flexible display, a laser printer, a telephone, a cell phone, a remote control apparatus, a pad computer, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display, a vehicle electronic apparatus, a large area wall display, an audio visual screen, a signal apparatus, a theater screen, a stadium screen, a personal digital assistant (PDA), an industrial computer, a point of sales (POS) system, a heads-up display, a fully transparent display and a touch display. 